Former Oklahoma wide receiver Kenny Stills aggravated the quadriceps injury [during Saturday's preseason game] that has plagued him throughout training camp and was forced to leave the game in the first half. Stills was also making his preseason debut after the quad, which he first hurt in the spring, kept him out of the first two games and most of training camp.

“Not much to say. It’s the same injury I was dealing with before,” Stills said, via ESPN.com.
It’s not known how long the Saints expect Stills to be out, but the lingering nature of the injury likely means that he’ll have to scale things back for a while in hopes of getting over the injury once and for all. (Pro Football Talk)